Conventionally, as a supporting device for supporting or mounting a fluid-pressure unit of a brake apparatus as an example of an object to be mounted to a vehicle (in-vehicle mounted object), there is known one containing a bracket (console) for mounting the fluid-pressure unit via elastic members (for example, refer to Patent Document 1). The bracket contained in the supporting device has tow plate plate-like parts (legs) that are generally perpendicular to each other. One of the two plate-like parts is fixed to a side part of the fluid-pressure unit via two elastic members. The one of the plate-like parts is provided with two notches that open in a direction of mounting the fluid-pressure unit to the bracket (vertical direction) so that the elastic members fixed to the fluid-pressure unit are held in the notches. On the other hand, an elongated hole is formed in the other of the two plate-like parts so that an elastic member, which is attached to a pin extending from a bottom part of the fluid-pressure unit, is inserted into the elongated hole. The bracket for mounting the fluid-pressure unit is fixed to a predetermined position of a vehicle body. By using those elastic materials and the bracket, a transmission of a vibration from the vehicle body to the fluid-pressure unit can be suppressed while reducing a space needed for mounting the fluid-pressure unit.                Patent Document: Japanese Laid-Open Patent Application No. 2004-521276        
However, even if the fluid-pressure unit as an in-vehicle device is mounted to the vehicle body by using the above-mentioned supporting device, it is difficult to completely suppress a vibration of the fluid-pressure unit while the vehicle is moving. That is, if the above-mentioned supporting device is used and when the vehicle is moving, especially, on a punishing road, the fluid-pressure unit vibrates to no small extent mainly in a direction indicated by an arrow in FIG. 1, that is, in a vertical direction indicated by the outline arrow in the figure with elastic members C, which are provided to the bottom part of the fluid-pressure unit A, serving as a support point. Hereinafter, the major direction of vibration of such an in-vehicle mounted object is referred to as “main vibrating direction”. In the above-mentioned conventional supporting device, since the notches D formed in the bracket B open in the vertical direction in FIG. 1, the elastic members C tend to move in a direction in which the elastic members C are separated from the notches due to the vibration, and, thereby, there may occur a case in which the vibration of the fluid-pressure unit A is further promoted. If the vibration of the fluid-pressure unit is increased, there may occur a noise problem or a stress generated in a brake tube extending from the fluid-pressure unit is increased.